1. Field of the Invention
An aspect of this disclosure relates to a composite integrated circuit for a secondary battery, a composite device for a secondary battery, and a battery pack.
2. Description of the Related Art
There exists a known battery pack including a protection integrated circuit (IC) that turns off a switching circuit inserted in series in a power supply line connected to a secondary battery to prevent discharging of the secondary battery, and a state detection IC for detecting a state of the secondary battery (see, for example, Japanese Laid-Open Patent Publication No. 2009-153238). A ground terminal of the state detection IC is connected to the power supply line at a position between the secondary battery and the switching circuit.
As described above, a battery pack may include a protection IC for controlling a switching circuit and a battery-side IC (in the case of Japanese Laid-Open Patent Publication No. 2009-153238, “state detection IC”) having a ground terminal connected to a power supply line between a secondary battery and the switching circuit. With this configuration, however, because the ground terminal of the battery-side IC is connected to the power supply line between the secondary battery and the switching circuit, the power consumption of the battery-side IC is not reduced even when the switching circuit is turned off by the protection IC to prevent discharging of the secondary battery. Accordingly, with this configuration, discharging of the secondary battery may continue due to the power consumption by the battery-side IC.